I am using Open Street Maps to show a map in my HTML5 application.
It uses a URL like this for the map tiles,
http://b.tile.openstreetmap.org/{Z}/{X}/{Y}.png
If I chose an area, say Auckland, New Zealand, how could I work out all of the values of Z, X, Y that would cover Auckland? I would be looking to write a script to go and grab all those images and cache them in an HTML5 database.
First of all, take a look at the tile usage policy section about bulk download. Secondly, this sort of caching is easily done using TileStache: configure a cache to render or fetch tiles from a certain source, then run tilestache-seed.py, passing in the bounding box (in WGS84 coordinates) and desired zoom levels, and you should end up with all needed tiles.
Related
I have a dataset with several hundred thousand lat/long points. I would like to render these points on a map for info-graphic purposes (as small dots or something similar).
This is not something that necessarily has to be interactive, or rendered in a browser. It's okay if it's just an image.
I know that attempting this with markers and Google maps would be tough... any other tools out there that would generate this type of map? Preferably free/open source?
Or, do you have a method to make this work with something like Google maps? I don't want to use a marker clusterer... I need to be able to see all of the points.
In short :)
Download and fire-up Quantum GIS
Add some background map (e.g. OSM WMS layer from http://129.206.228.72/cached/osm)
Have your data in a CSV file, in WKT format, and load it on top (using add delimited text layer)
Save as image
You might want to peek what stackexchange.com has on GIS, too.
I am doing some research for what Map API to use for a coming project.
The main requirement is the ability to lock a map, and the ability to disable parts of the map.
Think about a special purpose map for Europe where I would like to disable and gray out the non-european countries.
A click on those grayed out areas should do nothing, meaning for all of the world except for Europe.
So, is it possible to disable large portions of the map?
Is it possible to add layers for the borders for each country, that is clickable, for instance on Germany?
I am looking at Bing or Google Maps at this point. Which one is more developer friendly one?
Bing looks so much nicer with the birds eye, much easier to read out the map and know what you are looking at. I find Googles full of clutter and always have problem knowing what I am looking at.
Possible approach(google-Maps): use a Polygon with multiple paths.
1 path for the entire world(vertices defined in clockwise order)
other paths for the enabled area(vertices defined in opposite clockwise order)
The result will be a polygon that covers the entire world with a hole for the enabled area. The map will not respond to click-events outside the enabled area(because it's covered by the polygon). The map will still respond to dblclick and zoom in, but this may be avoided by cancelling the propagation of the dblclick-event of the polygon.
It wouldn't be possible to gray out the dissabled area, but you could use the fillColor of the polygon to signalize which part of the map is disabled.
Is it possible to place (say 1000) markers (using set of LAT-LONG values) on Static Google map image?
Also, is there some sort of HTTP POST method to achive this or URL is the only way to go?
Basically, I was looking into Bing maps REST service - Imagery and I found that maximum 100 pushpins (markers) can be placed on to Bing map.
I would like to generate static map with unlimited markers/pushpins. Google or Bing does not matter.
Something like this: http://msdn.microsoft.com/en-us/library/ff701724.aspx#code-snippet-19
As far as I know there is no limit on how many markers you can add to a google-maps based map - however the performance of your map will decrease when you add a lot of them.
There is a nice article on developers.google.com (https://developers.google.com/maps/articles/toomanymarkers) that shows how to deal with lots of placemarks by either clustering them or rendering them on a separate layer.
The documentation for static maps states:
URL Size Restriction
Static Map URLs are restricted to 2048 characters in size. In practice, you will probably not
have need for URLs longer than this, unless you produce complicated maps with a high number
of markers and paths. Note, however, that certain characters may be URL-encoded by browsers
and/or services before sending them off to the Static Map service, resulting in increased
character usage. For more information, see Building a Valid URL.
I am pushing over 16000 markers with no problem at all, not even performance. I am using the javascript API, as long as you can put that into a variable, and push it to the canvas at a reasonable pase (1 per seccond is the speed i am pushing the markers ) there's no problem
The question is pretty descriptive.
I am working on a website that provides locations for filming.
All the data in the site is currently stored in a MySQL database including geocode data for google maps.
I need to show polygon areas for the different london boroughs that has locations.
I have all the data as kml files, idealy i would like to store this in the MySQL database.
I have had success using fusion tables to display this data, but it seems silly to me to have to have this data duplicated on google just to use a fusion map layer, can i simply use a kml layer to render this data rather than having to create a fusion table and rendering it from that?
If so, is there a resource someone could point me to for more information?
UPDATE:
Thank you for the responses so far, i thought i would update the question with a little more info .
I eventually want to have all the areas displayed at the same time on my map and then when an area is clicked on ideally it would take you to another page on the website showing locations for that specific area.
I had initially tried using KML layers but i was getting errors saying my KML was invalid.
The KML was initially stored in a field in my database table, i think probably the errors were due to me not understanding exactly how google read in the KML data.
Using polygons would be far simpler to implement as i can get this data via JSON and then render the polygons from that.
I know now its not possible to have info windows with polygons, but i would just prefer to jump directly to another website page with info for that particular area using a click handler rather than show an info window.
Alternatively as suggested showing a tool-tip with a brief description of the area and a link to the page would be better, how the tooltip itself, is it possible to render on top the map?
I am slightly worried that I will reach the layer limit for the KML.
Is it possible to have multiple polygons rendered with KML on one layer, or do i need a separate layer for each clickable area?
The Google Maps API provides a pretty straightforward method to draw polygons.
Basic Example:
var polygon = new google.maps.Polygon({
map: your_google_map_instance,
paths: array_of_latlng_points,
fillColor: "#336699",
fillOpacity: .5,
})
EDIT: For this approach, you would need to parse your KML files (sorry, must've missed that when I first read it). You can import the KML files to a KML layer
You can overlay Polygons using KmlLayer, FusionTablesLayer (as you know), or native google.maps.Polygon objects.
KmlLayer and FusionTablesLayer render them as tiles, so for lots of Polygons (if you only need click events) will be more efficient. There are limitations on the number of KmlLayers that can be displayed on the map at one time and on FusionTablesLayer (but those don't seem to be causing you problems).
There are also third party parsers available for KML (geoxml3, geoxml-v3) which will take your KML and render it as native google.maps.Polygon objects. For lots of Polygons, this will be less efficient than tile based rendering, but it does allow mouseover/mouseout, and changing the properties of the Polygons dynamically.
You could also try data layers what have lots of events so you can display tooltips, info window, status text on various mouse events.
See samples in documentation:
https://developers.google.com/maps/documentation/javascript/datalayer
If you have many polygons (where the actual value of many depends on multiple factors, can be anywhere between 100 and 1,000) the best is to use a built in layer type. The fastest are the ones rendered on server, e.g. kml layer because this doesn't create hundreds of DOM elements in browser but still exposes click events so infoboxes can be displayed for each item.
In the worst case you can implement your own rendering with an image map, obviously by using an existing library like mapnik.
https://developers.google.com/maps/documentation/javascript/maptypes#ImageMapTypes
I have a number of events in the US. I have addresses for these events, but it varies in accuracy. Some might be the full address, some might be just "Austin, Texas".
I'd like to plot these programatically on a map on a webpage with a marker as they'll change fairly regularly. The marker should be an internal link to the relevant row in the table of events lower down on the page.
The image doesn't need to be updated on the fly, just on the (say fortnightly occasions) when an event is added (e.g. a cached image is cleared and recreated)
Rather than use Google maps, I'd like to plot these on top of an image like this: http://0.tqn.com/d/geography/1/0/9/H/usa3.jpg
How would I go about putting markers on this image that correspond to the (rough) geolocation of these events?
Your best bet might be to use google maps and plot the locations and then just pull an image of the map - that way you can let google do all the work of placing the pins but not have to worry about people zooming, since it is a static image file.
Beyond that, you can type the locations into any mapping service to get a rough idea of the location and then place markers or dots on your map file in the same location. This would allow you to choose whatever image or color you want the icons/markers to be, since you will find and place them yourself.